[PATCH 3/5] combine: add regno field to LOG_LINKS
Segher Boessenkool
segher@kernel.crashing.org
Fri Nov 14 19:29:00 GMT 2014
With this new field in place, we can have LOG_LINKS for insns that set
more than one register and distribute them properly in distribute_links.
This then allows many more PARALLELs to be combined.
Also split off new functions can_combine_{def,use}_p from the
create_log_links function.
2014-11-14 Segher Boessenkool <segher@kernel.crashing.org>
gcc/
* combine.c (struct insn_link): New field `regno'.
(alloc_insn_link): New parameter `regno'. Use it.
(find_single_use): Check the new field.
(can_combine_def_p, can_combine_use_p): New functions. Split
off from ...
(create_log_links): ... here. Correct data type of `regno'.
Adjust call to alloc_insn_link.
(adjust_for_new_dest): Find regno, use it in call to
alloc_insn_link.
(try_combine): Adjust call to alloc_insn_link.
(distribute_links): Check the new field.
---
gcc/combine.c | 135 ++++++++++++++++++++++++++++++++++------------------------
1 file changed, 80 insertions(+), 55 deletions(-)
diff --git a/gcc/combine.c b/gcc/combine.c
index c4d23e3..cf184db 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -328,6 +328,7 @@ static int *uid_insn_cost;
struct insn_link {
rtx_insn *insn;
+ unsigned int regno;
struct insn_link *next;
};
@@ -346,12 +347,13 @@ static struct obstack insn_link_obstack;
/* Allocate a link. */
static inline struct insn_link *
-alloc_insn_link (rtx_insn *insn, struct insn_link *next)
+alloc_insn_link (rtx_insn *insn, unsigned int regno, struct insn_link *next)
{
struct insn_link *l
= (struct insn_link *) obstack_alloc (&insn_link_obstack,
sizeof (struct insn_link));
l->insn = insn;
+ l->regno = regno;
l->next = next;
return l;
}
@@ -686,7 +688,7 @@ find_single_use (rtx dest, rtx_insn *insn, rtx_insn **ploc)
if (INSN_P (next) && dead_or_set_p (next, dest))
{
FOR_EACH_LOG_LINK (link, next)
- if (link->insn == insn)
+ if (link->insn == insn && link->regno == REGNO (dest))
break;
if (link)
@@ -982,6 +984,43 @@ delete_noop_moves (void)
}
+/* Return false if we do not want to (or cannot) combine DEF. */
+static bool
+can_combine_def_p (df_ref def)
+{
+ /* Do not consider if it is pre/post modification in MEM. */
+ if (DF_REF_FLAGS (def) & DF_REF_PRE_POST_MODIFY)
+ return false;
+
+ unsigned int regno = DF_REF_REGNO (def);
+
+ /* Do not combine frame pointer adjustments. */
+ if ((regno == FRAME_POINTER_REGNUM
+ && (!reload_completed || frame_pointer_needed))
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
+ || (regno == HARD_FRAME_POINTER_REGNUM
+ && (!reload_completed || frame_pointer_needed))
+#endif
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+ || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
+#endif
+ )
+ return false;
+
+ return true;
+}
+
+/* Return false if we do not want to (or cannot) combine USE. */
+static bool
+can_combine_use_p (df_ref use)
+{
+ /* Do not consider the usage of the stack pointer by function call. */
+ if (DF_REF_FLAGS (use) & DF_REF_CALL_STACK_USAGE)
+ return false;
+
+ return true;
+}
+
/* Fill in log links field for all insns. */
static void
@@ -1015,67 +1054,39 @@ create_log_links (void)
FOR_EACH_INSN_DEF (def, insn)
{
- int regno = DF_REF_REGNO (def);
+ unsigned int regno = DF_REF_REGNO (def);
rtx_insn *use_insn;
if (!next_use[regno])
continue;
- /* Do not consider if it is pre/post modification in MEM. */
- if (DF_REF_FLAGS (def) & DF_REF_PRE_POST_MODIFY)
- continue;
+ if (!can_combine_def_p (def))
+ continue;
- /* Do not make the log link for frame pointer. */
- if ((regno == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
- || (regno == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- || (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
-#endif
- )
- continue;
+ use_insn = next_use[regno];
+ next_use[regno] = NULL;
- use_insn = next_use[regno];
- if (BLOCK_FOR_INSN (use_insn) == bb)
- {
- /* flow.c claimed:
-
- We don't build a LOG_LINK for hard registers contained
- in ASM_OPERANDs. If these registers get replaced,
- we might wind up changing the semantics of the insn,
- even if reload can make what appear to be valid
- assignments later. */
- if (regno >= FIRST_PSEUDO_REGISTER
- || asm_noperands (PATTERN (use_insn)) < 0)
- {
- /* Don't add duplicate links between instructions. */
- struct insn_link *links;
- FOR_EACH_LOG_LINK (links, use_insn)
- if (insn == links->insn)
- break;
+ if (BLOCK_FOR_INSN (use_insn) != bb)
+ continue;
- if (!links)
- LOG_LINKS (use_insn)
- = alloc_insn_link (insn, LOG_LINKS (use_insn));
- }
- }
- next_use[regno] = NULL;
- }
+ /* flow.c claimed:
- FOR_EACH_INSN_USE (use, insn)
- {
- int regno = DF_REF_REGNO (use);
+ We don't build a LOG_LINK for hard registers contained
+ in ASM_OPERANDs. If these registers get replaced,
+ we might wind up changing the semantics of the insn,
+ even if reload can make what appear to be valid
+ assignments later. */
+ if (regno < FIRST_PSEUDO_REGISTER
+ && asm_noperands (PATTERN (use_insn)) >= 0)
+ continue;
- /* Do not consider the usage of the stack pointer
- by function call. */
- if (DF_REF_FLAGS (use) & DF_REF_CALL_STACK_USAGE)
- continue;
-
- next_use[regno] = insn;
+ LOG_LINKS (use_insn)
+ = alloc_insn_link (insn, regno, LOG_LINKS (use_insn));
}
+
+ FOR_EACH_INSN_USE (use, insn)
+ if (can_combine_use_p (use))
+ next_use[DF_REF_REGNO (use)] = insn;
}
}
@@ -2347,7 +2358,19 @@ adjust_for_new_dest (rtx_insn *insn)
/* The new insn will have a destination that was previously the destination
of an insn just above it. Call distribute_links to make a LOG_LINK from
the next use of that destination. */
- distribute_links (alloc_insn_link (insn, NULL));
+
+ rtx set = single_set (insn);
+ gcc_assert (set);
+
+ rtx reg = SET_DEST (set);
+
+ while (GET_CODE (reg) == ZERO_EXTRACT
+ || GET_CODE (reg) == STRICT_LOW_PART
+ || GET_CODE (reg) == SUBREG)
+ reg = XEXP (reg, 0);
+ gcc_assert (REG_P (reg));
+
+ distribute_links (alloc_insn_link (insn, REGNO (reg), NULL));
df_insn_rescan (insn);
}
@@ -2777,7 +2800,9 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
SUBST (PATTERN (i2), XVECEXP (PATTERN (i2), 0, 0));
SUBST (XEXP (SET_SRC (PATTERN (i2)), 0),
SET_DEST (PATTERN (i1)));
- SUBST_LINK (LOG_LINKS (i2), alloc_insn_link (i1, LOG_LINKS (i2)));
+ unsigned int regno = REGNO (SET_DEST (PATTERN (i1)));
+ SUBST_LINK (LOG_LINKS (i2),
+ alloc_insn_link (i1, regno, LOG_LINKS (i2)));
}
}
@@ -13865,7 +13890,7 @@ distribute_links (struct insn_link *links)
struct insn_link *link2;
FOR_EACH_LOG_LINK (link2, place)
- if (link2->insn == link->insn)
+ if (link2->insn == link->insn && link2->regno == link->regno)
break;
if (link2 == NULL)
--
1.8.1.4
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